The invention concerns a fluid conduit connecting device for medical purposes, particularly for the connection of the blood circuit of a patient to an external circuit for blood filtering or other blood treatment.
A great number of patients today depend on blood filtering appliances. A common cause for this is acute renal failure, i.e. a non functional kidney system. Patients with this diagnosis may either receive a transplanted kidney or be treated with dialysis. Before transplantation comes into the question, the patient is however obliged to use dialysis. This is also the only solution for many patients due to the fact that transplantation is not feasible for one reason or the other and due to the shortage of kidneys available for transplantation. Thus, in Sweden today approximately 1600 patients are regularly treated with dialysis. This means a great strain, not only to the patients themselves, as it brings about frequent appearance at the hospital and stay at the premises during a period of at least three to four hours. It also brings about great costs for the society, the annual costs for one patient in dialysis may today be estimated to SEK 500 000. A very large part of the costs relate to personnel, equipment and premises and it is therefore desired to be able to conduct the treatment in the homes of patients, which would lead to great economic gain.
Of the different systems available today for conducting blood filtering one equipment may be mentioned which leads the blood from a blood vessel of the patient, transports it by means of an external pump through a blood treatment equipment and thereafter reinjects it into the patient.
Another solution is continuous ambulatory peritoneal dialysis, where an existing membrane in the body, which could be the abdominal membrane, is used. In this case blood is present on one side of the membrane, at the same time as a solution of salt and glucose, acting as a purifying liquid, is introduced to the other side of the membrane.
For the treatment of acute renal failure, continuous arteriovenous hemofiltration (CAVH) has recently been used. The principle of this method is continuous filtration of the blood, with the heart of the patient being used as the pump for pressing the blood through an external so called shunt circuit, wherein the blood is continuously filtered. After filtering the blood is reintroduced to the patient in a purified state.
All known systems to be the connected to the blood circuit of the patient are associated with drawbacks of different kinds. The problem of sterility is particularly serious, since all kinds of external equipment being connected to a patient bring about a risk of introducing infections .into the blood circuit. As an example of a device for the connection of an external circuit to a blood circuit of a patent European Patent document No. EP-A2-0 087 189 could be mentioned, wherein an external member comprising two needles is inserted into a housing, through a self-sealing septum, the housing being transplanted into the body of the patient. The insertable needles of this device involve a substantial risk of introducing infections into the blood stream of the patient. In known types of shunt devices, conventional tube joints are used, being connected to inserted or transplanted connections for artery and vein respectively in the patient.
U.S. Pat. No. 4,496,350 describes a connecting device, where the needles are protected by a displaceable protective member for preventing the openings of the outer portions of the needles from exerting cutting action on the blood leakage preventing septum. Also this device brings about a great risk of introducing infections into the blood stream.
A different kind of connecting device is described in Swedish patent document No. SE-B-453 801 wherein a connecting half with artery or vein connections is implanted into the patient, and from the outside is connectable to an external circuit by means of an external connecting half, which is designed as a naked male portion, insertable into the implanted connecting half so as to allow CAVH-treatment.
In all these known devices the connections are unfortunately sources of infections that could be introduced into the patient despite the latter device comprising arrangements for sterilization.
There are also problems of sterility in connections of the external circuit and when connecting different sources of fluids to a patient.